Field of the Invention
This invention relates generally to pumps of the combined centrifugal-vortex type, and more particularly to pumps incorporating one or more vortex impeller paths arranged in series flow relation with at least one centrifugal pump flow path.
U.S. Pat. Nos. 2,982,986 and 2,983,432 both to Myron D. Tupper, and both assigned to the assignee of the present application, disclose blowers of the combined centrifugal-vortex impeller type incorporated in a vacuum cleaner, the objective in each case being to provide a blower combining the relatively low head and high flow characteristics of a centrifugal impeller with the high head and low flow characteristics of a vortex impeller.
Conventional vortex impellers, such as those incorporated in the above-referred to Tupper patents, employ a single, annular vortex channel thus providing a vortex airflow path of substantial length. The rate of flow and efficiency of such conventional vortex impellers are limited by reason of friction losses due to the length of the vortex airflow path.
It is desirable to provide a blower or pump of the combined centrifugal-vortex impeller type having increased efficiency and also having a higher flow characteristic without a corresponding reduction in head generating capability.
It is accordingly an object of the invention to provide an improved pump of the combined centrifugal-vortex impeller type.
Another object of the invention is to provide an improved pump of the combined centrifugal-vortex impeller type employing multiple vortex paths.
Yet another object of the invention is to provide a centrifugal-vortex impeller pump wherein both the centrifugal and vortex impeller blades may be of the same outer diameter when desired, or may fully utilize the impeller's maximum diameter.
Still another object of the invention is to provide a pump with a substantial increase in the flow rate capability and efficiency thereof without a significant reduction in head capability.